The present invention concerns a cooling arrangement of the type disclosed in U.S. Pat. No. 4,320,798, wherein a heat exchanger that has seawater flowing through it and fresh water flowing around it is installed in a housing as well as a storage tank with a short-circuit duct for fresh water and a thermostat for the temperature control of the fresh water.
An object of the present invention is to further develop the aforementioned known advantageous arrangement in a way that, with the lowest cost of construction, the cooling and the temperature control of the lubricating oil is combined into one individual part of the cooling of the engine coolant consisting of the fresh water.
This and other objects of the invention are obtained by providing a cooling arrangement for a liquid-cooled internal combustion engine with combined seawater-fresh water cooling comprising a first heat exchanger means for seawater-fresh water heat exchange and a second heat exchanger means for seawater-lubricating-oil heat exchange, housing means within which the first and second heat exchanger means are arranged, the housing means including an inlet duct, a short-circuit duct and a thermostat for fresh water, and wherein an additional thermostat and an exchange filter for the lubricating oil are provided adjacent to the first and second heat exchanger means.
In the disclosed, preferred embodiment a storage tank means is also provided within the housing means in fluid communication with the first heat exchanger means. The housing means is a one-piece housing. In this manner, a compact structural unit is obtained in the housing means of which the storage tank means, both heat exchanger means and the thermostat for the fresh water as well as their connections can be developed largely in one piece with the housing means. This reduces exposed connections in regard to number as well as in regard to length and thus content of the seawater, fresh water and lubricating oil which reduces not only the cost of construction but also the weight of the cooling arrangement. Finally, it also reduces the space requirement.
According to a further feature of the present invention, the first and second heat exchanger means are arranged behind one another in the flow direction of the seawater in respective chambers of the housing means. The chambers are arranged opposite one another and separated by a partition having an opening through which the first and second heat exchanger means are connected. Flange means are provided for fastening the thermostat for the fresh water and the first and second heat exchanger means in the housing means and the partition thereof serves as an inside bearing point about the opening therethrough for the first and second heat exchanger means. Further, the first and second heat exchanger means are each formed as slide-in parts with outside mounting flanges and connections and inside cylindrical connecting and support pieces, the latter being arranged and sealed concentrically within one another and in the opening of the partition. This arrangement guarantees that especially the heat exchanger means with sea water flowing through their interiors, which customarily require relatively short-term maintenance or replacement, can be exchanged with good access and relatively little work. The same is true for the inserts of the thermostats for fresh water and lubricating oil and for the exchange filter for the lubricating oil attached to the one-piece housing.
In the disclosed embodiment of the invention the thermostat for fresh water is arranged in an additional housing chamber of the housing means that is essentially abreast of the second heat exchanger means with ducts for fresh water being provided from the first heat exchanger means and from the short-circuit duct to the thermostat for fresh water in the area of the partition. Lubricating-oil ducts are also provided between the second heat exchanger means and each of the thermostat and the exchange filter for the lubricating oil. The oil ducts are arranged on the outside at the housing chamber of the second heat exchanger means and the additional housing chamber for the thermostat for fresh water. The thermostat and the exchange filter for the lubricating oil are arranged on the outside at the additional housing chamber for the thermostat for fresh water. This makes possible a space-saving arrangement of the ducts and thermostats for fresh water and lubricating oil as well as of the exchange filter for the lubricating oil in the area of the heat exchanger means for lubricating oil. In the area of the heat exchanger means for fresh water, space is therefore saved for other auxiliary aggregates of the engine.
As an additional feature of the invention, at least one of the lubricating-oil ducts leads into the lower area of the housing chamber for the second heat exchanger means and has a course with a high point at the level of the upper area of the housing chamber. This prevents an undesirable emptying of the contents of the lubricating-oil heat exchanger means into the oil pan when the engine is not in operation.
A lubricating-oil filter head and the exchange filter are flanged to the outside of the housing means with the lubricating-oil filter head containing the thermostat for the lubricating oil. This arrangement is advantageous for the maintenance of the engine and the construction of the cooling arrangement. In addition to a thermostat for the lubricating oil, a lubricating-oil filter head also customarily contains control elements for the pressure control of the lubricating-oil circulation so that the resulting control system in the lubricating-oil filter head would have to have an accumulation of material that is disadvantageous for the casting process in the area of the lubricating-oil ducts that have to be mechanically treated. The exchange of the lubricating-oil filter head in the case of operational disturbances and of the exchange filter as the customary maintenance process benefits from this development.
The storage tank means is connected with the inlet duct, the short-circuit duct and the housing chamber for the first heat exchanger means by a narrow venting and volume-balancing opening. The storage tank means also has inlet and outlet openings for connection with a venting connection and with the suction-pressure area of the cooling circulation of the engine, respectively. Further, the inlet duct, short-circuit duct and the housing chamber of the first heat exchanger means have a direct connection for a connecting line to the outlet of a cooling jacket of the engine, and the additional housing chamber of the thermostat has a connection for a connecting line to the suction area of the cooling circulation of the engine. This results in an inside structure and a connection of the cooling arrangement to the cooling system of the engine that largely ventilates the engine as well as the circulating content of the cooling arrangement.
These and other objects, features and advantages of the present invention will become more apparent from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, one embodiment in accordance with the present invention .